THE MAIN STAGES OF THE PROJECT



It is a long term project:

  • Feasibility study at the Ecole Polytechnique Fédérale de Lausanne (EPFL) in 2003
  • Announcement of challenge on 28 November 2003
  • Development of concept in 2004-2006
  • Design and manufacturing of the prototype HB-SIA in 2007-2009
  • Test flights and first night flight with the prototype in 2010
  • Construction of the HB-SIB airplane in 2011
  • Missions of several days, crossing of the Atlantic and tentative tour of the world completing in five stages from 2012


Since the spring of 2005, flights in real weather conditions have been carried out at the Royal Institute of Meteorology of Brussels and at Geneva airport, for the 2007 simulation. These virtual flights enable the evaluation of the aircraft's energy resources to fly through a whole night, and come back into the sun each morning in order to continue its mission. To be able to do this generally means following a tortuous flight path to avoid cloudy zones on the trajectory.

The Solar Impulse will gain altitude during the day and descend during the night, thereby economising an important quantity of energy in its batteries. These maximum and minimum altitudes will have to be defined in terms of security parameters and meteorology. A complete feasibility analysis of the airplane and the security of the missions is therefore being carried out to identify the weak points, risks, redundancies and to find solutions that will guarantee the success of the real missions.

In 2007-2009, the manufacturing of the prototype HB-SIA with a 63 metre wingspan is envisaged, equipped with a non-pressurised cabin to validate the selected technologies. For the first mission tests, the test pilots will take over the controls of this airplane with this disproportionate wingspan to examine its flight characteristics. It will then be a question of demonstrating the feasibility of the night flight with a solar airplane. Never before has an aircraft of this type succeeded in making a night flight with a pilot on board, and this mission of 36 hours will represent an historic first!

In 2011, an second airplane will be made with a pressurised cabin to enable non-stop, long-haul missions, continental crossings and that of the Atlantic Ocean.

The round-the-world flight will be the high point of this series of great firsts. Take-off should happen in 2012, on a flight over land close to the equator, but essentially in the northern hemisphere.

Five stopovers are planned to change pilots and present the adventure to the public and also the political and scientific authorities. Each flight leg will last from 3 to 4 days, which is considered to be the maximum a single pilot can endure.

Once the efficiency of the batteries will allow the reduction of weight, the airplane could seat two pilots for very long flights and a non-stop, round-the-world flight could be envisaged at that stage.